The present invention relates to tires. More particularly it relates to a tire having a rim protector acting as an anchorage point for at least one carcass-type reinforcement structure.
The reinforcement of tire carcasses is currently formed by one or more plies (conventionally termed “carcass plies” from the manufacturing process in the form of semi-finished products as plies), provided with cord reinforcements which are usually radial. The anchoring or support of these plies or reinforcements is effected conventionally by turning up a portion of the ply around a bead wire disposed in the bead of the tire.
Furthermore, there are currently tires which do not have the traditional turning-up of the carcass ply around a bead wire, nor even a bead wire in the traditional sense of this element. For example, the specification EP 0 582 196 describes a means of contriving a carcass-type reinforcement structure in the beads, by disposing adjacent to the reinforcement structure circumferential filaments, the whole being embedded in a rubber anchoring or bonding mix, preferably with a high modulus of elasticity. Various arrangements are proposed in this specification. The specification further refers to tires manufactured without the aid of semi-finished products in the form of plies. For example, the cords of the various reinforcement structures are applied directly to the adjacent layers of rubber mixes, the whole being applied by successive layers on to a core having a form whereby it is possible to obtain directly a profile related to the final profile of the tire being manufactured. Thus, in this case, rather than “carcass plies” in the conventional sense, more specifically “carcass-type reinforcements” are found.
The anchoring of the reinforcement structure or carcass ply (if the tire is assembled with various semi-finished products, including a carcass ply) is of particular importance in order to ensure durability of the tire. The realisation of durable and reliable anchorage often involves using a large area of the bead and using high-quality materials, which is therefore costly. The presence of cord windings or a bead wire further implies a large mass.
Furthermore, the specifications of motor vehicle manufacturers on the one hand and standards in force in the various countries on the other mean that, for a tire of a given dimension, one finds a rim also of given dimensions. These technical standards mean that it is more difficult to get away from the usual compromise of the conventional anchoring found in tires of known types. The manufacturers of tires therefore generally use other architectural elements than beads and anchorings in order to optimise the features of the product.